You prepare a standard solution of ferrous ammonium sulfate that is 50.0 ppm in

Question

You prepare a standard solution of ferrous ammonium sulfate that is 50.0 ppm in Fe. You pipette aliquots of 0.50 mL, 1.00 mL, 2.00 mL, 4.00 mL, 8.00 mL, and 10.00 mL into 100-mL volumetric flasks, add 1 mL of hydroxylamine solution, 3 mL of o-phenanthroline solution, and suffIcient citrate to adjust to pH 3-4 as described in your laboratory instructions. After diluting each sample to the loo mL mark, and allowing time for the color to develop, you record the absorbances shown in the table. The data is a bit scattered. Looks like your pipetting ability could use some improvement. However, you can still use this data as a calibration curve. Plot the data in Excel, obtain a trendline and the equation for the linear regression line. Print the graph with the equation and turn in to your laboratory instructor with your name and section printed at the top. Use this graph to answer the following questions: The equation for the line is in the form y = mx + b, where m is the slope, and b is the intercept. What is the slope of the line? (Neglect units). 0.132 What is the intercept of the line? (Neglect units). 0.0886 You next add 50 mL of your unknown sample to a 100 mL volumetric flask, treat it with hydroxylamine, o-phenanthroline, and citrate as described above, dilute to the mark, and determine the absorbance of the diluted sample to be 0.637 What s the concentration of Fe in your unknown?

Explanation / Answer

YOU HAVE 0.637 THAT IN THE FE IN THE TABLE IS : 4.0 BUT YOU ADD 50 ML OF YOUR UNKOWN SAMPLE TO A 100 ML VOLUMETRIC FLASK

y=0.132(0.637)+0.0886=0.172684

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.